Seniors striving to stay sharp, parents looking for drug-free ways to help kids with learning disorders, brain injury patients, burn victims, business executives, and athletes are all turning to computer apps, games, and programs for a mental edge.

While a handful of early experiments have hinted that brain training might offer some benefits, experts caution that the claims behind many brain training games and apps have far outstripped what science has been able prove. And so far, the industry has operated largely unnoticed by federal regulators.

Consumers can end up spending large amounts of money on these programs, part of a $1.3 billion industry that’s growing rapidly every year.

What are they getting in return?

“I look at it, to some degree, like the supplement industry, you know, where people are scrambling to take this, that, and the other supplement, and there’s not a lot of data showing that these supplements have that much of a positive impact,” says Peter Finn, PhD. He's a clinical psychologist and expert in substance abuse at Indiana University in Bloomington. The National Institutes of Health just awarded Finn a $2.3 million grant to study whether brain training to boost working memory might help alcoholics and other substance abusers.

“It’s unethical,” he says.

And many brain researchers agree with him. Last week, an international group of 69 neuroscientists and psychologists penned an open letter to caution consumers that the claims being made by the brain-game companies aren’t scientifically proven.

Even so, many serious scientists -- including at least one who signed that letter -- are equally reluctant to completely dismiss brain training, which they believe has real promise, if not definitive proof.

And researchers are hot on the trail of that proof. In the last fiscal year alone, the government funded at least $5 million in brain training studies. The studies are testing the approach as a remedy for everything from schizophrenia to substance abuse. That doesn’t include many more millions being spent by private companies hoping to sell brain training programs to consumers.

“I’m a little afraid that if the message is too strong -- that this is all a bunch of made-up stuff -- then we have the risk of throwing the baby out with the bathwater,” says Adam Gazzaley, MD, PhD. He's a professor of neurology and a brain game developer at the University of California, San Francisco.

The Business of Brain Training

Barely a decade old, the industry that says you can bulk up your mind like a muscle is thought to be one of the fastest expanding segments of the technology market. With annual growth in the range of 20% to 25% each year, brain training has blossomed from a $210 million business in 2005 to one that was worth $1.3 billion in 2013, according to SharpBrains, a market research firm.

Market leader Lumosity, which charges $15 a month or $80 a year for access to its brain games, has doubled its revenue every year since 2007. The company recently said it had reached 45 million members around the world.

More than just memory games, though, different forms of brain training are being tried by athletes, fighter pilots, soldiers recovering from head injuries, burn victims, and children with ADHD and other learning disorders.

The explosive growth has been driven by consumers who download "edutainment" apps and programs to their computers, tablets, and smartphones.

Ann Stewart, a 66-year-old retired real estate executive in Berkeley, CA, is one of them.

Nearly half the people who try brain training are adults over age 50, like Stewart, who are just hoping to keep their mental abilities sharp for as long as they can.

“I always thought my brain was one of my more trustworthy assets,” she says. But then names became harder to recall. And she started doing absent-minded things that shook her sense of self-reliance, like returning a carton of eggs to the freezer instead of the fridge.

So Stewart signed up for a study of a new brain training game, and after that ended, she continued to play other brain games. She estimates she spent $200.

She has since switched to a free app for the games, though she can’t point to any noticeable benefits.

“I wanted to keep doing something, and an ounce of prevention is worth a pound of cure in my brain,” she says.

About half of consumers who’ve tried “serious” brain training games aren’t sure they got what they bargained for, according to a survey by SharpBrains.

And about 10% of people -- like Cindy Siegel -- feel cheated by the claims made by brain training companies. Siegel, who lives in Montclair, NJ, spent $10,000 on a brain training program called LearningRx in an effort to help her teenage daughter, Brianna, who has problems with working memory, dyslexia, and auditory processing. Working memory involves using information to make decisions and solve problems.

“They promised that we would have incredible results,” Siegel says. Those claims are spelled out in the company’s promotional materials that promise “life-changing results” that treat “the root cause of learning struggles like ADHD and dyslexia.”

Brianna worked one-on-one with a LearningRx coach for 2 hours at a time, 3 days a week. She also did exercises at home on the computer.

After almost a year, though, she was still failing her classes, her teachers noticed no improvement in her schoolwork, and she felt more frustrated and discouraged than ever.

“It didn’t help her one iota,” Siegel says. “They prey on the fact that they know you're desperate.”

Tanya Mitchell, the vice president of research and development for LearningRx, contends that Brianna’s case is unusual.

She says most students who participate in their programs improve about 15 or 20 percentile points after 90 hours of training.

“We consistently get a very good result. She just happens to be an exception,” Mitchell says.

Weak Science and Few Protections for Consumers

The Federal Trade Commission regulates advertising claims that companies make about their products. When asked specifically about its regulation of brain-training products, an FTC spokesperson said the commission doesn't speculate about whether it will take action in a particular area.

A spokesperson for the Food and Drug Administration (FDA) said brain games that pose a low risk, such as those intended to help improve cognition (mental skills like thinking, remembering, and learning), “would likely fall under the agency’s enforcement discretion.” Higher-risk games -- those intended to diagnose or treat a specific disease -- “may require FDA oversight to assure that such specific therapies and diagnosis are safe and effective.” She adds, “We encourage companies who have questions to come talk with us.”

“What’s unfortunate is that there might be something that has value, but we have to sort of understand what it is,” Finn says. “We want to be careful and do the good science so you can say, ‘OK, this is how it works and this is who it helps,” he adds.

The problem is that much of the “science” touted by companies that sell brain training games is weak or biased. Companies often do their own studies to test their products, so there’s a profit motive to find positive results. Many studies have too few participants to be statistically valid.

Another red flag is whether the studies have been published in reputable medical journals that are reviewed by outside researchers who scrutinize the results. But other so-called “predatory” journals, with slick-sounding names, will publish virtually any paper -- for a hefty fee. It can be hard for the average person to tell the difference between the two.

On industry leader Lumosity’s web site, for example, customers can click on a tab to “Learn More About the Research.”

Of the 13 completed studies they list, one trumpets the benefits of the company’s brain training exercises in the classroom. Researchers had more than 800 students do 10 hours of training with Lumosity games over the course of the semester. The company’s researchers said those students showed greater improvements than the roughly 400 other students who didn't get the training.

But improvements on what? The kids scored better on the Brain Performance Test, an assessment that was also created by Lumosity. The company didn’t look at what happened to the kids’ grades or their standardized test scores.

Daniel Sternberg, PhD, a study author and senior data scientist with Lumosity, explained that the Brain Performance Test is a computerized version of standard neuro-psychological assessments.

“The tested tasks are distinct from our games and are designed to measure underlying cognitive abilities like working memory, visual attention, and processing speed,” he said in an email to WebMD.

But outside researchers say there’s no reason the company couldn’t have used existing -- and scientifically accepted -- tests to measure the kids’ performance, rather than make up their own.

“If these companies were serious about doing a real test of their product, they would fund an independent agency to supervise these studies and would have the studies done by a researcher that is skeptical about the product,” says Randall Engle, PhD. He's a psychology professor at Georgia Institute of Technology who regularly tests and often debunks the science behind brain training programs. “If there is improvement under those circumstances, then it is probably real.”

Can You Train a Better Brain?

Engle’s research has helped give Georgia Tech a reputation as a proving ground for brain training programs.

Inside a squat beige building on the fringes of its Atlanta campus, college students play computer games with electrodes attached to their heads as researcher Eric Schumacher, PhD, looks on. He’s part of a $12.7 million trial called Strengthening Human Adaptive Reasoning and Problem Solving (SHARP) that’s being done in collaboration with the University of New Mexico and Charles River Analytics, the Boston-based company that developed the games.

The researchers involved in the study are pursuing one of the holy grails of brain training. They hope to show that people don’t just get better at playing the video games, but that the games -- if played with a low-voltage zap of electricity to the brain -- can actually make people better thinkers.

In other words, they want to know if the approach can boost the brain’s fluid intelligence.

Fluid intelligence refers to a person’s ability to be mentally nimble, to absorb facts and ignore irrelevant information to correctly solve problems and make good decisions.

Studies show that fluid intelligence peaks at age 22, and then begins a slow, plodding decline.

Engle recently completed a different study of a working memory training program.

People who signed up could earn a bonus each day they showed improvement.

The star of that study, he says, was a Georgia Tech sophomore he called Nick. Over the course of 20 days, Nick got so much better that his results literally shot off the chart.

“This guy came up with strategies for doing this that were just amazing,” Engle says. “He got really good at the games.”

But when they looked at his scores for fluid intelligence, his line from day 1 to day 10 to day 20 was completely flat.

“He got a lot better at the test, but he’s not any smarter,” Engle says.

It is a result he’s seen time and time again.

“What we find over and over and over again, in testing literally a thousand subjects in these training studies, is that we have never found a benefit in intelligence, attention control, etc. You get some subtle differences in tasks that are somewhat similar to the tasks that are trained, but just nothing that would suggest that this training has a benefit that would generalize to real life,” Engle says.

What the Research Shows

In one of the largest studies to date on brain training, researchers at Cambridge University assigned more than 11,000 people to one of two different brain training regimens, or to a control group that was just asked to answer challenging questions on the computer. The brain games were designed to mirror the kinds of exercises available through companies like Lumosity, CogniFit, and Fit Brains. They challenged short-term memory, planning, reasoning, problem solving, visuo-spatial skills, and math.

After 6 weeks, the researchers found that people who did the brain training got better at the games they played, but they didn’t get any smarter, overall. That is, any benefits they got from brain training didn’t extend to real life. It was published in 2010 the journal Nature.

Which is not to say that brain training trials come up completely empty.

In another study, published last year in Nature, UCSF professor Gazzaley proved that a brain training game he developed, called NeuroRacer, could help seniors improve their ability to multitask. What set Gazzaley’s study apart was that he showed that the improvements people saw could carry over into daily life and that the effect of training was still there even 6 months after participants finished.

A few other studies have shown lasting benefits.

A study published earlier this year in the Journal of the American Geriatrics Society found that seniors who participated in brain training to enhance memory, reasoning, and processing speed still performed better than a control group 10 years after the study ended. The study was sponsored by the National Institutes of Health.

But neither NeuroRacer nor all of the exercises used in the NIH-sponsored study are yet available to the general public.

Researchers are trying to bring versions of those exercises to consumers. Gazzaley is working to make a new version of his program called Evo. He hopes to get FDA approval for EVO as a medical device, and offer it to patients through doctors and other medical providers.

Technologies, Though Still Experimental, Are Already in Consumers' Hands

Still, Schumacher of Georgia Tech isn’t sure that improving fluid intelligence is an impossible goal, especially if people get a little help from electricity.

The technology is called transcranial direct current stimulation, or tDCS. It’s a low voltage current -- just 2 milliamps -- that’s passed between two electrodes attached to the scalp. There’s some evidence tDCS may alter how the brain functions, affecting which brain chemicals are released and how neurons fire. Studies have shown it makes meditating easier by helping the brain ignore irrelevant information, for example -- and it may even improve a person’s performance when they play first-person-shooter video games.

It remains to be seen, though, whether tDCS, when combined with brain training, might move the needle on fluid intelligence.

What’s more, the risks of zapping the brain with electricity, even at such a low voltage, are also not well-understood. Some experts have cautioned that the technology might lead to seizures and mood changes.

Companies like foc.us and The Brain Stimulator offer tDCS home kits to anyone who wants to try them. Another company, called Thync, just announced that they’d raised $13 million to bring a tDCS device to consumers.

SharpBrains CEO Alvaro Fernandez says he isn’t surprised that so many people are rushing ahead of the science to adopt brain training technology.

“One big problem is the health care system,” he says. “In the U.S., cardiovascular health has made huge strides over the last 40 or 50 years. But everything from the neck up has been completely ignored.”

With diagnoses of mental disorders like ADHD and dementia rising, he thinks the demand for services that may help the brain will only increase.

“Many users feel like they’re not properly helped by health providers and they are stepping up and thinking, ‘How do we do things ourselves?’ because they don’t necessarily trust their health providers.”

But even Fernandez, who thinks the concept of brain fitness will one day be as common and as accepted as physical exercise, says the industry may be promising more to consumers than it can currently deliver.

“In principle, everyone can benefit from this, just like everyone can improve their physical fitness, but it has to be personalized and it has to be relevant to the individual, but we’re not there right now,” he says.